There is no current way of allowing a machine, such as a bulldozer or the like, to use real-time surface information for automatic machine control guidance system calculations. In the past, the actual surface generated by such a machine has been surveyed, after the machine has worked an area. It will be appreciated that surveying a worksite is time consuming.
Aerial photogrammetry methods have used lasers to map three dimensional terrain models. Using these methods, it has been possible to achieve 10 cm (3.94 inches) relative standard deviations of generated surfaces. This is not accurate enough for precise machine control applications, especially when absolute accuracies are required.
Current three dimensional control guidance systems use pitch from the design in control calculations for operation of the machine. However, the design surface does not always match the pitch of the actual surface on which the machine is operating. Prior art machine guidance systems map a surface generated by the machine by deriving surface information on the assumption that the blade cutting edge is skimming the surface. It will be appreciated that this is not always an accurate assumption.
Currently, the only way to measure machine control system performance is to survey the surface of the worksite before and after the machine is operated to re-contour the surface. While some prior art systems suggest scanning the area in front of a machine for avoidance detection or for determining the best cut locations for digging and determining machine locations, such as shown in U.S. Pat. Nos. 6,363,173, and 6,363,632, respectively, such systems do not provide for enhancement of machine operation and measurement of machine performance.